Slow-running reversible piston-engines operating on compressed fluid or the like



3,220,316 ENGINES OPERATING ON Nov. 30, 1965 H. KUMMERMAN SLOW-RUNNING REVERSIBLE PISTON COMPRESSED FLUID OR THE LIKE Filed Aug. 15, 1963 3 Sheets-Sheet 1 INVENTOR KU MM ERMAN HENF?! 3,220,316 SLOW-RUNNING REVERSIBLE PISTON-ENGINES OPERATING 0N H. KUMMERMAN Nov. 30, 1965 COMPRESSED FLUID OR THE LIKE Filed Aug. 13, 1963 5 Sheets-Sheet 2 INVENTOQ HUMMEQMAN HENRI BV N 3 1955 H. KUMMERMAN 3,220,316

SLOW-RUNNING REVERSIBLE PISTON-ENGINES OPERATING ON COMPRESSED FLUID OR THE LIKE Filed Aug. 13, 1963 3 Sheets-Sheet 5 IN VENTOQ HENRI KUMMEFPMAN l 3,220,316 Ce Patented Nov. 30, 1965 8 Claims. Cl. 91-176) It is the essential object of the present invention to provide a high-torque, slow-running reversible piston-engine operating on compressed fluid or the like, this invention being also concerned With the various applications of an engine of this character.

Many types of engines, notably hydraulic motors of the positive displacement type, have already been proposed. As a rule these engines are characterized by a relatively high rotational speed and a relatively low torque, so that they are ill suited for certain specific applications and to a direct take-off from their power shaft, unless cumbersome heavy and costly means such as reducing gears are interposed. This is the case notably of the joint positive control of hatchway cover panels on board ships, which open and close automatically and move as a rule at a relatively low speed involving relatively high engine torques. In these specific instances it is frequently necessary to use specially designed electromotors or separate hydraulic cylinders or the like, which are costly and sometimes complicated to manufacture, operate and mount, while requiring particular cares for their control and maintenance.

It is the essential object of the present invention to avoid the drawbacks set forth hereinabove by providing a reversible engine operating on compressed fluid such as hydraulic fluid, which is of the type using reciprocating pistons slidably mounted in a plurality of singleor double-acting cylinders, this engine being preferably of the slow-running type providing a relatively high torque.

The engine according to this invention is remarkable notably in that said cylinders are pivotally mounted respectively at their cylinder-head end about stationary axes, by means of trunnions rigid with the engine crankcase, so that said cylinder may oscillate about said stationary axes, each one of said reciprocating pistons being axially rigid with its piston-rod constituting and associated connecting-rod pivoted at its end opposite to said piston on a power shaft provided with cranks and constituting a crankshaft or the like receiving directly the thrust from the pistons, said cylinder providing preferably a relatively long stroke for said pistons and oscillating in a plane parallel to the perpendicular to said crankshaft. Thus, due to the relatively long piston stroke providing an advantageous lever arm as a consequence of the use of a crankshaft instead of an eccentric shaft which would lead to prohibitive dimensions, a high torque and a high mechanical efficiency are attained, inasmuch as the use of a crankshaft affords a direct axial thrust of the pistons rigid with their connecting-rods.

According to another feature characterizing this invention, the aforesaid movable cylinders are arranged separately or by groups, in line and/or radially (partly or completely) along said crankshaft, and at least some of said cylinders are spaced angularly from the others in radial directions about said crankshaft, said connecting rods being pivoted separately on crankpins respectively separate from, and/or common to, at least some of said connecting-rods, and the substantially in line cylinders are pivoted preferably on said trunnions aligned with, or common to, at least some of said cylinders. Furthermore,

two or more cylinders of the singleor double-acting type 7 may be provided.

In order to keep the over-all dimensions and the final cost within reasonable limits, the engine broadly described hereinabove comprises, according to another feature of this invention, for instance, three single-acting cylinders of which two are disposed substantially in line and pivoted on a common axis, the third cylinder being so disposed that its pivot axis is shifted angularly, for example by in relation to the common pivot axis of said first pair of substantially in-line cylinders. With this cylinder disposal a relatively short and particularly rigid crankshaft is obtained, which is capable of properly resisting distortion under heavy piston loads while having relatively moderate over-all dimensions.

According to a compemental feature of this invention, and with a view to obtain the proper geometrical configuration corresponding to an equal angular spacing of the three cylinders, said crankshaft comprises two chankpins spaced angularly preferably 120 apart, one of said crankpins having a single width (or axial length of pin or bearing) adapted to receive the connecting-rod big-end bearing of only one of said three cylinders, the other crankpin having twice this width for receiving the separate connecting-rod big-end bearings of the remaining two cylinders.

To obtain a torque curve having a harmonic characteristic with substantially sinusoidal waves, and according to another feature of this invention, the connecting-rod bigend bearing of one of said pair of substantially in-line cylinders is pivotally mounted on said single-width crankpin and the connecting-rod big-end bearings respectively of said other in-line cylinder and of said angularly shifted cylinder are mounted preferably independently of each other on the same double-width crankpin aforesaid, said angularly shifted cylinder being disposed for example between the other two.

This engine meets particularly well the low-speed and high-torque conditions required for many applications.

This invention is also concerned with the various practical applications of engines of the type set forth hereinabove, notably for operating hatchway closing panels on ships or the like.

,With the foregoing and other objects in View, the invention resides in the novel arrangement and combina tion of parts and in the details of construction hereinafter described and claimed, it being understood that changes in the precise embodiment of the invention herein disclosed may be made within the scope of what is claimed without departing from the spirit of the invention.

Other objects and advantages will become apparent from the following description taken in conjunction with the accompanying drawings in which:

FIGURE 1 illustrates diagrammaticaly in longitudinal section an engine constructed according to a specific form of embodiment of this invention, the cylinders being seen from the outside with some parts shown in section;

FIGURE 2 illustrates diagrammatically a cross section of the engine shown in FIGURE 1 the section being taken upon the line 11-11 of FIGURE 1, the inlet and outlet ports of the distributor being coplanar with the port connected to the cylinder for the sake of convenience and to facilitate the understanding of the mode of operation.

FIGURE 3 is a diagrammatic detail view showing in section taken upon the line III-III of FIGURE 4 and on a larger scale the distributor of the engine with the camshaft as seen from one end;

FIGURE 4 is a diagrammatic detail view showing in longitudinal section taken upon the line IVIV of FIG- URE 3 the distributor with the actual position of the inlet and outlet ports, and

FIGURE is a diagrammatic front view showing on a larger scale the distributor drive.

In the specific form of embodiment illustrated in FIG URES 1 and 2 of the drawing the engine unit is enclosed in a fluid-tight case designated by the reference numeral 1 and stiffened if desired by means of adequate ribs. The access to the inner space of case 1 may behad through an aperture 2 adapted to be closed by means of a detachable cover 3 secured by means of screws 4 or the like. T his case comprises a base plate 5 constituting the bed of the engine and adapted to be rigidly secured on a suitable support.

In the case 1 a crankshaft 6 constituting the power shaft of the engine is mounted and supported by mean-s of a pair of coaxial end bearings 7, 8 secured on the case 1. The first end bearing 7 consists for example of a fixed sleeve 9 rigid with the case wall and enclosing a rollingconta-ct bearing 10 preferably of the needle type in order to provide a bearing of relatively reduced axial dimension, the needle or like bearing 10 being retained by a flanged end-plate 11 carrying a shaft packing or like sealing device 12 and secured by means of screws or like fastening member 13 on the sleeve 9.

The other end bearing 8 is advantageously of the detachable type to permit the mounting and removal of the crankshaft 6 and consists of a detachable sleeve or like member 14 secured for example by means of fiat fillister-head machine screws 15 engaging countersunk holes in the case 1, the bore of said sleeve receiving likewise a need-1e bearing 10 retained by a flanged end plate 11 secured by screws 13 and provided with a shaft packing or like sealing device 12.

Preferably, the case 1 constitutes an oil sump for lubricating the cylinders according to the dipper or splash method, the bearings 7, 8 comprising to this end oil ducts 16 preferably of the immersed type for lubricating the needle bearings.

The crankshaft 6 comprises the two stub shafts 17, 18 projecting respectively from the case ends to constitute power take-offs, said stub shafts being provided to this end with a key groove or like means 19.

Thescrankshaft 6 comprises two successive crankpins 20, 21 for example contiguous and shifted angularly to each other by approximately 120. Crankpin 20 for example is designed to have a single width; in other words the length of its journal portion is such that it can receive only one connecting-rod big-end bearing, and the crankpin 21 has twice the width of said crankpin 20, so that it can receive two connecting-rod big-end bearings disposed side by side on the same crankpin journal.

The engine comprises preferably three movable cylinders 22,23, 24 enclosed in said fluid-tight case 1 and having their cylinder-head ends pivoted on trunnions substantially parallel to the crankshaft axis and mounted inside said case, whereby said cylinder can each oscillate about said trunnions. To obtain reduced over-all dimensions and therefore a relatively compact case 1 and an engine configuration dynamically consistent with the engine operation, two of these cylinders for example cylinders 22 and 23, are pivoted on preferably aligned trunnions forming if desired a single common trunnion 25, and the third cylinder 24 is pivoted on another trunnion 26 parallel to the crankshaft axis and shifted about the latter by an angle of about 120 with respect to the axis of trunnion 25.

Each cylinder may consist very simply of a tubular body or sleeve 27 having a cylinder head closed by a fixed bottom member constituting a cylinder-head 28 whereby the cylinder is pivotally mounted on its relevant trunnion. Slidably mounted in the bore of each cylinder 27 is a piston on like member 29 of which the lateral fluid-tightness with respect to the inner wall or bore of the cylinder is ensured by suitable annular packings or piston rings 39 fitted in a circular groove 31 of each piston. Each piston 29 is axially rigid with a piston-rod 32 extending coaxially with the piston and constituting in fact a connecting-rod.

To this end, the connecting-rod 32 comprises for example at its small end a shouldered or like portion 33 which is a tight fit in a corresponding axial bore 34 of piston 29 and locked in position for example by means of a retaining or spring ring 35 constituting an external shaft locking member of the snap ring type circlip ,or the like, this ring being fitted in a corresponding groove formed in the projecting end of said shouldered or like end portion 33. The inner fluid-tightness between the portion 33 and bore 34 of piston 29 may be ensured by means of a packing ring 36 fitted in a circular groove 37 formed in the aforesaid shouldered portion 33.

Each. cylinder 27 is closed at its end adjacent to the crankshaft by a preferably detachable member 38 formed for example with a male shouldered tapered portion 39 so as to contact a corresponding female shouldered tapered portion formed in the inner end of the cylinder bore. This member 38 is locked in position for example by means of an internal shaft locking member of the snap ring type circlip or the like, this ring engaging a corresponding circular groove formed in said inner end of the cylinder bore. This member 38 has an axial bore 41 formed therein through which the connecting-rod 32 is a slide fit, whereby said member 38 acts as an axial guide bearing to said connecting rod; said member 38 is advantageously provided with a plurality of regularly spaced holes 42 parallel to its axis and disposed on a common circumference centered on said axis, to permit the lubrication of the cylinder concerned according to the dipper or splash method.

Each connecting-rod 32 has its end opposite to said piston 29 rigidly assembled with a big-end bearing 43 comprising for example a flange or like element 44 screwed on a shouldered and screw-threaded end portion 45 of connecting-rod 32, and locked in position by means of a pin or like fastening member 46 extending through the hub of said flange 44 and through said shouldered end portion 45. This flange 44 carries two bearing shells 4'7, 48 constituting or lined with the bearing bushings, whereby the connecting-rod big-end is mounted on the journal portion 49 of the relevant crankpin (see FIGURE 2). These two shells are assembled with each other and with the flange 44 by means of fitted screws or bolts 50, or the like. Of course, this method of assembly or mounting should not be construed as limiting the scope of this invention, as any other equivalent mounting may be resorted to without departing from the scope of the invention.

To impart the necessary dynamic balance and uniformity in the rotational movement of the engine unit consisting of the three cylinders 22, 23 and 24 and the two bearing crankshaft 6, the connecting-rod big-end bearing 51 of one of the cylinders 22 of the pair of cylinders 22, 23 oscillating coaxially ismounted on the crankpin 20 having a single bearing width or'axial length, and the bearings 52 and 53 of the connecting-rod bigends of the other cylinder 23 and of the cylinder 24 shifted angularly by of the aforesaid pair of cylinders, are both mounted on a common crankpin 21 having twice the length or axial width of said crankpin 20, however in such a manner that the two adjacent bearings are rotatably movable independently of each other on the journal portion of cranklin21. Cylinder 24 is disposed preferably in such a manner that its big-end bearing 53 lies between the big-end bearings 51 and 52 of the other two cylinders.

The case 1 comprises advantageously three partial partitions or ribs 54, 55, 56 preferably notched along their free edge 57 and forming somewhat with the side walls of the case three compartments communicating with each other and adapted to receive respectively the three cylinders 22, 23 and 24, these partitions or ribs being also adapted to constitute end or intermediate supports or brackets for the trunnions 25 and 26 of the cylinder heads. To simplify the construction and reduce its cost,

the three cylinders 22, 23 and 24 are preferably of the single-acting type. To this end, each cylinder head 28 has formed therein a port 58 for feeding or exhausting the working chamber 59 of the cylinder overlying the piston 29. This port 58 is connected through a swivel union 60 or the like of any known and suitable type and through a flexible hose 61 to a distributor 62 of hydraulic oil under pressure for producing the cyclical periodic supply to and exhaust from the three successive cylinders in a predetermined order.

This distributor 62 comprises a case 63 secured by means of a flange 64 on the outer lateral wall 65 of the engine case 1 for example by means of locked screws 66 or the like. The flexible hoses 61 extend through the wall 65 by passing through a hole 65a formed therein. Rotatably mounted in said case 63 is a camshaft 67 preferably parallel to the axis of crankshaft 6 and comprising a stub shaft 68 projecting into the engine case 1 and having keyed thereon means for rotatably driving said camshaft, for example a chain sprocket 69 retained on the stub shaft 68 by means of an end lock ring 70 of the circlip or like type. This sprocket may be driven through a roller chain transmission or the like 71 from a driving sprocket 72 keyed on the adjacent end of crankshaft 6. The two driving and driven sprockets 72, 69 respectively have preferably the same teeth characteristics, that is, the same number of teeth, to provide a 1:1 transmission ratio. Under these conditions the camshaft 67 is driven at the same angular velocity as crankshaft 6. The camshaft 67 carries three eccentric cams 73, 74 and 75 shifted angularly by 120 from one another about the axis of camshaft 67. As a rule and irrespective of the number of cylinders contemplated for the engine, the number of cams carried by the camshaft 67 will be equal to the number of engine cylinders and these cams will be shifted angularly and at regular relative intervals from one another about the axis of said camshaft.

Each cam aforesaid is adapted to operate, preferably by direct contact, a slide-valve forming plunger piston or the like, shown in the drawing as being slidably mounted in a corresponding bore of the distributor case 63. Under these conditions, the number of plunger pistons or slide valves will be the same as that of engine cylinders, i.e. three in the example shown and described herein, as designated by the reference numerals 76, 77 and 78 these plunger pistons being mounted in corresponding bores 79, 80 and 81 of the distributor case. Each assembly consisting of a plunger and of the relevant bore constitutes a slide valve or like device (see FIGURES 3 and 4).

Associated with each slide valve is an engine cylinder and each slide valve is adapted to open or close the communication between the associated engine cylinder on the one hand and the source of compressed fluid or the return sump or fluid return line on the other hand. To this end, the cylindrical bores 79, 80 and 81 of the distributor are provided with ports 82, 83 and 84 connected each through a corresponding flexible hose 61 to the relevant engine cylinder. In the specific form of embodiment illustrated each bore of said distributor comprises two coaxial circular cylindrical cavities constituting annular grooves 85 and 86 of larger diameter, which are adapted to act as inlet and outlet passages respectively and mutually, and all the grooves located at the same level, for example the lower grooves 85, communicate with each other through a manifold passage 87 leading into a port 88 formed in the distributor case, and the cavities or grooves 86 of a higher level in said bores communicate with each other through another manifold 89 opening into another port 90 formed in the distributor case. The two ports 88 and 90 of the distributor case may constitute respectively and mutually inlet and outlet ports for the compressed fluid and to this end they can be connected selectively through a suitable control valve or the like and through pipe lines 91, 92 to a source of compressed fluid, such as a pump, compressor or the like, and also 6 to a return sump or chamber constituting the fluid reservoir (for example an oil-filled reservoir) or the like.

Each slide valve slidably mounted in the corresponding bore has at least one longitudinal passage formed through it for balancing the pressures exerted on either side of its end faces. Each slide valve is urged for engagement with its lower face against the corresponding cam by suitable elastic means consisting preferably of a return compression coil spring 94 or the like, which is prestressed and mounted between a cavity 95 formed at the relevant upper end of the slide valve and a detachable cap 96 secured by means of screws or the like on the distributor for closing the upper ends of the bores. These caps are formed with inner studs 97 for centering the springs 94.

Each slide valve aforesaid comprises a substantially narrower intermediate cylindrical portion 98 having a smaller diameter than that of the lateral sliding faces 99 of the slide valve which extend on either side of this intermediate portion, the latter being disposed substantially at midlength of the slide valve. This narrower intermediate portion forms together with the inner wall of the corresponding slidevalve bore and annular space adapted, according to the momentary position of said slide valve, to connect by turns the port 82, 83 or 84 connected to the relevant cylinder with either of the aforesaid cavities or 86, i.e. with either of the inlet or outlet ports 88 and or vice versa. The respective and mutual use of the ports 88 and 90 as inlet and outlet ports for the compressed fluid depends on the direction of rotation of the engine and may also be determined beforehand by the operator. This constructional disposal of the distributor elements is applicable to singleacting power cylinders. Of course, by resorting to obvious and suitable arrangements, as far as the shape and dimensions of the slide valves and the number and relative arrangement of the distributor ports are concerned, double-acting cylinders may also be used.

The shape and dimensions of the slide valves and of their associated cams as well as the relative direction of said cams in relation to the aforesaid crankshaft are such that when, during the engine operation, one of said slide valves is at mid-stroke, the piston of the cylinder associated therewith is at one of its two dead centres, i.e. at its top or bottom dead centre, the two ports 85 and 86 being closed simultaneously in this case. At this time the continuity of operation or rotation of the engine is provided for by one of the other cylinders which is under pressure. During the following time period the slide valve moves in one or the other direction, as determined beforehand by the operator, and the cylinder associated therewith communicates immediately with one of the ports 88 or 90, or with the other, constituting either an inlet port for introducing compressed fluid, or an exhaust or delivery port.

In the case of a hydraulic motor, the liquid consisting as a rule of oil is practically incompressible, so that a hydraulic lock or locking effect is likely to occur as a consequence of the building up of a fluid lock or plug at the top dead centre or bottom dead centre of the piston stroke, if the slide valve associated with the cylinder considered in a specific case is not constantly properly timed with the proper kinematic sequence of successive movements as a consequence of constructional defaults or imperfections due for instance to inadequate machining tolerances. Since it is desirable, for economical reasons, to cope with such minor inconveniences, it is essential to provide means for definitely avoiding any hydraulic locking or like lock effect, such as the mechanical means described hereinafter.

When the piston moving in a cylinder approaches the top of its stroke, it is desirable that the movement of the corresponding slide valve takes place with a certain time lag in relation to its proper theoretical position with respect to the crankshaft, so that said piston may continue its motion through the top dead centre postion before the exhaust port be completely closed. However, since this operative sequence must be reversed at the lower end of the piston stroke, or in other Words since the corresponding slide valve should then be in advance with respect to its proper theoretical position in relation to the crankshaft, this requirement can be met neither through the known lost-motion contrivances which can only be. unidirectional, nor though the overlapping of the slide valve which produces a temporary short-circuit or by-pass with concomitant impulses having a sinusoidal characteristic which lead to a drop in the final efliciency of the motor.

To meet the above-mentioned requirement the endless roller chain 71 acting as a transmission member between the driving sprocket 72 keyed on the crankshaft 6 and the driven sprocket 69 keyed on the distributor shaft has a certain excess length or extra-length, in lieu of the proper theoretical length calculated from the distance between centres of the driven and driving sprockets (see FIGURE The two chain reaches 100, 101 extending between the aforesaid pair of pinions 72 and 69 respectively, mesh respectively with two small loose sprockets 102 and 103 preferably of same size co-acting each. with one of the aforesaid chain reaches. These loose sprockets are mounted for loose rotation on pins or journals 104, 105 respectively having eccentric axes with respect to the pitch circles of the sprocket teeth; in addition, these sprocket axes are mutually so positioned that when the chain reach coacting with one of them is remotest from the centre of rotation of the loose sprocket associated therewith, the other chain reach co-acting with other loose sprocket is nearest to the centre of rotation thereof, with corresponding interm'ediate positions. On the other hand, the pitch diameter of these two identical loose sprockets is substantially one-third of that of the main sprockets 72 and 89, so that as one run of the chain is riding the peak of its co-relating eccentric idler sprocket while the opposite run is riding the heel of the other eccentric idler sprocket with appropriate inter-positional relationship, the chain slack will be taken up six times per revolution of the large sprockets 69, 72, i.'e. three times on each side. This causes the driven sprocket 69 to be alternatively advanced or delayed in relation to the master or driving sprocket 72. Thus, starting from the relative positions of the endless chain and idler sprockets shown in FIGURE 5 wherein the chain run 101 rides the peak of idler sprocket 103 when the driving sprocket 72 is assumed to rotate in the clockwise direction, for example, so as to stretch the chain run 101, the actual exc'ess length of the deflected run 101 which is the. driving or tight side of said chain 71, will be progressively reduced whereby this deflected run will gradually straighten out so that the linear displacement of any one tooth of the driving sprocket 72 will serve for one part to straighten out the run 101 and for the other part to move the driven sprocket 69 the rotation of which will, therefore, correspondingly lag behind sprocket 72 until the idler sprocket 103 has turned by half a IEVOlll. tion (corresponding to a rotational displacement of onesixth of revolution for the driving sprocket 72) whereafter the chain run 101' will now ride the heel of idler sprocket 103. Then, the length of chain run 101 will again grow progressively longer upon continued rotation of sprockets 72 and 103, whereby in a reverse manner, the lengthening of chain run 101 will be effective to accelerate the rotation of the driven sprocket 60 which will thus lead ahead of the driving sprocket 72 until it has turned by another half of revolution whereafter this cycle is repeated. Therefore, it will be seen that in consideration of the idler sprockets 102, 103 being of one-third the pitch diameter of the main sprockets 72 and 69, there will be three impulses per crankshaft revolution which will delay the valve gear and three impulses that will advance it, these lag and lead impulses following one another alternately.

As a rule, when the number of engine cylinder is at least two, the pitch diameter of the aforesaid pair of loose sprockets 102, 103 will be one fraction of the pitch diameter of said main sprockets 72, 89 mounted on the crankshaft and on the distributor crankshaft respectively this fraction being of such value that the numerator of the fraction is one and its denominator equal to the number of engine cylinders.

With this arrangement the above-mentioned hydraulic lock or locking effect is definitely avoided and furthermore the over-all efficiency is increased by reducing the counter-pressure to a minimum value, even in case of zero hydraulic locking effect.

The general arrangement of parts described hereinabove constitutes a long-stroke engine of relatively reduced overall dimensions, of which the crankshaft may be used as a direct take-off or drive member without interposing any intermediate reducing mechanism.

By way of example and without considering this application as limiting the scope of the invention, an engine of this type may be mounted on board ships for control ling the opening and closing movements of hatchway cover panel assemblies. In this case the engine according to the present invention may have for example the following over-all dimensions:

Over-all crankshaft length 597 mm. (23%") With a rated oil pressure of about 210 kg./sq. cm. (3,000 p.s.i.) the minimum torqu'e will be about 575 kgm. (4,150 ft./l-b.) therotationa-l speed 11 r.p.=m. and the oil output at this speed about 21 l./min. (5.55 US. gallons per minute).

Of course, although the present invention has been described in conjunction with a preferred embodiment, it is to be understood that modifications and variations may be resorted to without departing from the scope of the in vention, as those skilled in the art will readily understand. Such modifications and variations are considered to be within the purview and scope of the invention and appended claims.

What I claim is:

1. A selectively reversible pressure fluid-operated, slow-speed, long-stroke and high torque, positive displacement motor comprising a fluid-tight case with a lower part forming an oil sump and with at least one pair of opposite Walls provided with two coaxially aligned bearings respectively, a rotary output multiple-throw crankshaft in said case, and journaled in said bearings, at least one end of said crankshaft forming an outer power take-off stub projecting outside from said case, said crankshaft being provided with a plurality of cranks having crank-pins at least some of which are angularly offset from each other along said crankshaft, a plurality of oscillating Working cylinders enclosed in said case and which are at least equal in number to that of said crankpins, each of said cylinders having a closed head end and an open bottom end and having means for pivotally mounting by its head end to said case for swinging motion about a radial pivot axis substantially parallel to said crankshaft, reciprocable single-acting pistons each having a head end face and a bottom end face and slidably mounted in said cylinders to define between the pistons head end faces and the cylinders closed head ends fluid expansible chambers, each cylinder head end having a single intake-and-egress port opening, piston rods coaxially with the bottom end faces of said pistons and rigidly extending from said bottom end faces outside from said cylinders and pivotally journaled to said crank-pins respectively, piston rod guide bearing members removably fitted to the bottom ends of said cylinders respectively and formed each one with an axial bore through which the relevant piston rod extends with a. sliding fit,

said guide bearing members being formed with passage means for permanent communication between the inner space of said case and the inside of their alotted cylinder for splash lubrication thereof, a control valve mechanism for sequentially controlling the flow of pressure fluid to and from said cylinders, said port in each cylinder being connected to said control valve mechanism by a hose pipe for alternately supplying pressure fluid to and exhausting fluid from said cylinder, distributing gear means for actuating said control valve mechanism in timed relation to the rotation of said crankshaft and including positive coupling means operatively interconnecting said crankshaft with said control valve mechanism, and an automatic speed control arrangement associated with said coupling means for continuously and cyclicly varying the running velocity of said distributing gear means to periodically and alternatively produce an exhaust lag for each cylinder with respect to the top dead center position of the piston and an exhaust lead relative to the bottom dead center thereof.

2. A device according to claim 1, wherein at least two of said cylinders are arranged alongside of each other and pivoted by said pivotal mounting means on the same axis, at least one remaining cylinder being in spaced angular relation to said two cylinders, the pistons in said remaining cylinder and one of said two cylinders having their respective piston rods journaled to the same one of said crank-pins.

3. A device according to claim 1, wherein said control valve mechanism comprises a plurality of juxtaposed spring-loaded, cam-actuated shuttle plunger valves, one for induction to and eduction from each cylinder, said valves being connected to said ports of said cylinders by said hose pipes, a rotary camshaft for sequentially operating said valves and extending in substantially parallel relationship with said crankshaft, at least one driven sprocket pinion carried by and rigidly connected to said cam-shaft, at least one driving sprocket wheel carried by and rigidly connected to said crankshaft in registering relationship with said sprocket pinion, at least one endless sprocket chain interconnecting and meshing with said sprocket wheel and pinion, said sprocket chain having a length in excess of the correct theoretically required length, and self-acting slack take-up and restoring means operatively connected to said sprocket chain for alternately delaying and advancing the speed of said sprocket pinion with respect to its rated value corresponding to invariable chain transmission characteristics.

4. A device according to claim 3 wherein said sprocket wheel and pinion are identical and said slack take-up and restoring means consist of two identical idler sprocket wheels meshing with both sides of said sprocket chain respectively, hub bearings rotatively supporting said idler sprocket wheels and which are eccentric to the pitch circle of the teeth of said idler sprocket wheels so as to provide thereon a peak and a heel which are respectively remotest from and nearest to the axis of rotation of the respective idler sprocket wheels, the angular position of said idler sprocket wheels relative to each other being such that when one side of said chain is riding the peak of its co-operating eccentric idler sprocket wheel, the opposite side is riding the heel of its co-operating idler sprocket wheel with corresponding interpositional relationships, whereas the pitch diameter of both idler sprocket wheels is a fraction of that of the just-named sprocket wheel and pinion, said fraction having its numerator equal to one and its denominator equal to the number of said cylinders.

5. A device according to claim 4 wherein said control valve mechanism comprises a valve-chest assembly secured to the outside of one of said case walls and formed with an inner cavity and with a plurality of substantially parallel identical valve bores arranged in line and equal in number to that of said cylinders and opening at one end in said cavity and being closed at their opposite ends by a detachable cover secured to said valve chest, each valve bore being peripherally formed with two axially spaced recessed annular channel grooves con stituting enlarged cylindrical trough portions of said valve bore and of which any one is a feed groove and the other is a discharge groove according to a preselected reversible direction of rotation of said cam-shaft, said valve-chest being formed with a pressure fluid inlet port communicating through a common intake manifold gallery with all said feed grooves and with a fluid outlet port communicating through a common exhaust manifold gallery with all said discharge grooves and with an equal plurality of delivery-and-return ports opening each one into one bore intermediate of said feed and discharge grooves thereof and connected each one to one cylinder through one of said hose pipes, said cam-shaft being rotatably mounted in said valve-chest and extending through said cavity with its center line substantially at right angles to those of said bores and having one stub end portion projecting outwards from said valve-chest into said case and carrying said driven sprocket pinion, said cam-shaft carrying an equal plurality of symmetrically shaped eccentric tappets angularly and evenly spaced thereabout, and an equal plurality of reciprocable valve members slideably mounted in saidvalve bores respectively and bias-springs mounted in said bores respectively and yieldably urging said valve members into endwise engagement with said tappets respectively, each valve member being formed with a substantially narrower cylindrical intermediate throating portion registering in the midstroke neutral position of said valve member with that wall portion of said valve bore which separates said feed and discharge grooves and having substantially the same axial length as said wall portion, thereby defining therewith an annular space always communicating with said delivery-and-return port and adapted upon reciprocation of said valve member to alternatively interconnect said delivery-and-return port with said feed groove and with said discharge groove, the relative angular setting of said tappets with respect to said crankshaft being such that when one of said slide valve members is substantially in its neutral position with both feed and discharge grooves closed the piston of the associated cylinder is at a dead center.

6. A device according to claim 5 wherein said throating portion of each valve member is located substantially mid-way of its overall length and each valve member is formed at its end which is remote from said cam-shaft with an axial bore opening through the end face of said valve member into the associated valve bore and with a longitudinal pressure balancing drain duct opening at one end into said axial bore and at its other end into said cavity through the relevant end face of said valve member, each bias-spring being a coil spring interposed between each valve member and the closed end of the valve member accommodating bore and seatingly received in said axial bore of said valve member.

7. A device according to claim 5, comprising a total number of three cylinders, two of which are pivoted on a single trunnion pin extending through the cylinder head ends and journaled in corresponding bearings supported by said opposite case walls respectively whereas the third cylinder is disposed at an angle of substantially apart from the two other and pivoted by its head end to a fixed bracket integral with said case, a fixed intermediate bearing for said single trunnion pin, said crankshaft being formed with two crank-throws angularly spaced at substantially 120 from each other, one of which has a single width suflicient to receive the big end bearing of one of said two cylinders, whereas the other throw is of double width to accommodate the separate big end bearing of the remaining cylinder.

8. A device according to claim 7 wherein at least one of said main crankshaft bearings is removably secured to said case, said valve-chest is formed with an attachment flange for detacliable connection with said case and said case is provided with an access hole closed by a removable cover.

UNITED References Cited by the Examiner STATES PATENTS Gardner 91182 Tobey 91180 McGrath 91176 10 Dickerson 91180 Herman 91176 Jones 91182 Feaster 91180 Zeibman 91176 Born 91180 Bennett 91176 Neil 91176 Thorpe 91176 Karde 123--55 X FOREIGN PATENTS Germany.

SAMUEL LEVINE, Primary Examiner.

FRED E. ENGELTHALER, Examiner. 

1. A SELECTIVELY REVERSIBLE PRESSURE FLUID-OPERATED, SLOW-SPEED, LONG-STROKE AND HIGH TORQUE, POSITIVE DISPLACEMENT MOTOR COMPRISING A FLUID-TIGHT CASE WITH A LOWER PART FORMING AN OIL SUMP AND WITH AT LEAST ONE PAIR OF OPPOSITE WALLS PROVIDED WITH TWO COAXIALLY ALIGNED BEARINGS RESPECTIVELY, A ROTARY OUTPUT MULTIPLE-THROW CRANKSHAFT IN SAID CASE, AND JOURNALED IN SAID BEARINGS, AT LEAST ONE END OF SAID CRANKSHAFT FORMING AN OUTER POWER TAKE-OFF STUB PROJECTING OUTSIDE FROM SAID CASE, SAID CRANKSHAFT BEING PROVIDED WITH A PLURALITY OF CRANKS HAVING CRANK-PINS AT LEAST SOME OF WHICH ARE ANGULARLY OFFSET FROM EACH OTHER ALONG SAID CRANKSHAFT, A PLURALITY OF OSCILLATING WORKING CYLINDERS ENCLOSED IN SAID CASE AND WHICH ARE AT LEAST EQUAL IN NUMBER TO THAT OF SAID CRANKPINS, EACH OF SAID CYLINDERS HAVING A CLOSED HEAD END AND AN OPEN BOTTOM END AND HAVING MEANS FOR PIVOTALLY MOUNTING BY ITS HEAD END TO SAID CASE FOR SWINGING MOTION ABOUT A RADIAL PIVOT AXIS SUBSTANTIALLY PARALLEL TO SAID CRANKSHAFT, RECIPROCABLE SINGLE-ACTING PISTONS EACH HAVING A HEAD END FACE AND A BOTTOM END FACE AND SLIDABLY MOUNTED IN SAID CYLINDERS TO DEFINE BETWEEN THE PISTONS'' HEAD END FACES AND THE CYLINDERS'' CLOSED HEAD ENDS FLUID EXPANSIBLE CHAMBERS, EACH CYLINDER HEAD END HAVING A SINGLE INTAKE-AND-EGRESS PORT OPENING, PISTON RODS COAXIALLY WITH THE BOTTOM END FACES OF SAID PISTONS AND RIGIDLY EXTENDING FROM SAID BOTTOM END FACES OUTSIDE FROM SAID CYLINDERS AND PIVOTALLY JOURNALED TO SAID CRANK-PINS RESPECTIVELY, PISTON ROD GUIDE BEARING MEMBERS REMOVABLY FITTED TO THE BOTTOM ENDS OF SAID CYLINDERS RESPECTIVELY AND FORMED EACH ONE WITH AN AXIAL BORE THROUGH WHICH THE RELEVANT PISTON ROD EXTENDS WITH A SLIDING FIT SAID GUIDE BEARING MEMBERS BEING FORMED WITH PASSAGE MEANS FOR PERMANENT COMMUNICATION BETWEEN THE INNER SPACE OF SAID CASE AND INSIDE OF THEIR ALOTTED CYLINDER FOR SPLASH LUBRICATION THEREOF, A CONTROL VALVE MECHANISM FOR SEQUENTIALLY CONTROLLING THE FLOW OF PRESSURE FLUID TO AND FROM SAID CYLINDERS, SAID PORT IN EACH CYLINDER BEING CONNECTED TO SAID CONTROL VALVE MECHANISM BY A HOSE PIPE FOR ALTERNATELY SUPPLYING PRESSURE FLUID TO 